This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 18 |
| 4 | 36 |
| 5 | 72 |
| 6 | 255 |
| 7 | 1152 |
| 8 | 2709 |
| 9 | 65535 |
| 10 | 294912 |
| 11 | 4294967295 |
| 12 | 4380480000 |